Francesco, Here is an example of what the setup for a layer looks like:<layer>
<name>Weather Observations</name>
<fields>Icon_used,URL,Type,OBJECTID</fields>
<linkfield>URL</linkfield>
<linkprefix></linkprefix>
<linksuffix></linksuffix>
<iconfield>Icon_used</iconfield>
<iconprefix>http://gislap134/FlexViewer2.2/assets/images/i_</iconprefix>
<iconsuffix>.png</iconsuffix>
<zoomscale>15000</zoomscale>
<forcescale>true</forcescale>
</layer>
The name element has to be the same as the label you gave that layer in the main config.xml